Golf club head with variable face thickness

ABSTRACT

A metal wood golf club head having a faceplate which is first cast or forged then CNC (computer numerical control) milled to a controlled thickness to form a precisely configured faceplate optimizing the sweet spot.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates generally to a metal wood golf club head, and more particularly, to a metal wood golf club head having a faceplate which is first cast or forged then CNC (computer numerical control) milled to a controlled thickness to form a precisely configured faceplate optimizing the sweet spot.

[0003] 2. Description of the Related Art

[0004] Golf club manufacturers have over the years made new and different designs for golf clubs to improve a golfer's performance. Different materials including metals for the “woods” have been used to increase ball flight distance and improve the feel of the club. Various weighting schemes, including perimeter weighting, have been proposed to optimize the center of gravity and moment of inertia of club heads. More recently, oversized club heads have been utilized to attempt to provide a large sweet spot on the ball striking face.

[0005] Perhaps the most important factor in hitting a golf ball well is the location of impact of the ball on the striking surface of the faceplate. A ball which is hit in the center of the sweet spot will generally go farther and straighter than a ball impacting near the heel or toe of the faceplate. A ball hitting face with a controlled thickness, and more particularly, a ball hitting face with its thickest region concentrated in the middle of the face, is desirable for achieving an efficient energy transfer to the golf ball and for providing a ball striking surface with greater strength and stability. One design of a metal wood golf clubs known in the art having a variable faceplate thickness is described in U.S. Pat. No. 5,474,296.

[0006] There is however a need for a method of making a golf club head having a face with controlled thickness to provide the required strength and stability, which is accurate and flexible to accommodate the need to achieve and/or change the desired thickness.

BRIEF SUMMARY OF THE INVENTION

[0007] The present invention provides a method of fabricating a metal wood golf club head with a controlled thickness faceplate and a golf club head made according to the method. The faceplate with a controlled thickness according to the present invention is accomplished by CNC milling the backside of the faceplate concentrically about a circular of oval shaped sweet spot at the center of the faceplate.

[0008] The faceplate of the present invention has a central portion with the maximum thickness and a peripheral portion with a reduced thickness. The reduction of thickness from the central portion to the peripheral portion is made gradually and accurately using the CNC milling process. The thickened central portion enables an efficient energy transfer upon impact with the golf ball without compromising the stability and weight balance of the club head.

[0009] The above described and many other features and attendant advantages of the present invention will become apparent from a consideration of the following detailed description in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A detailed description of the invention will be made with reference to the accompanying drawings wherein:

[0011]FIG. 1 is a perspective view of the golf club head of the present invention;

[0012]FIG. 2 is a view of the front of the faceplate of the golf club head of FIG. 1

[0013]FIG. 3 is a cross-sectional view taken along lines 3-3 of FIG. 2;

[0014]FIG. 4 is a cross-sectional view showing the backside of the faceplate; and

[0015]FIG. 5 is an exploded perspective view of the golf club head according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] FIGS. 1-5 show a golf club head 10 in accordance with the present invention. The golf club head 10 is assembled from a sole plate 12, a faceplate 14, a top plate 16 and a hosel 18; the sole plate 12 has a rear wall portion 20, a toe portion 22 and a heel portion 24. The hosel 18 is positioned in the hollow interior of the golf club head at the joint between the heel portion 24 of the sole plate 12 and to faceplate 14 and is formed and placed in the club head to receive a golf club shaft. The hosel 18 is preferably aligned with or offset from the center of gravity of the club head 10. The materials used to form the components of the club head 10 include steel, stainless steel, titanium, and other metallic materials having similar or better strength and resilience properties.

[0017] The backside 28 of the faceplate 14 of the golf club head 10 as shown in FIG. 2 has a central portion 30 as indicated by the circle, and a peripheral portion 32. The central portion 30 is the area that has the maximum cross-sectional thickness on the faceplate 14. In one embodiment of the present invention, the thickness in the central portion 30, the area within the circle, is uniform and is between about 2.5 mm to 5 mm and optimally about 3.0 mm as indicated at T₁ in FIG. 3. The thickness from the radial edge of the central portion 30 to the peripheral portion 32 is gradually decreased so that the thickness in the thinnest portion T₂ of the peripheral portion 32 reduces by between 0.25 mm and 1.5 mm, and by way of example for a optimal thickness of 3 mm at T₁, T₂ is about 2.5 mm in FIG. 3.

[0018] The faceplate 14 with controlled thickness according to the present invention is prepared utilizing the CNC milling technique. The faceplate 14 is first formed by either forging or casting. Such processes are well known in the art. In one embodiment of the invention, the faceplate 14 is slightly convex and the front side of the faceplate 14 has a plurality of horizontal grooves 34. The horizontal grooves 34 are designed to provide improved traction upon impacting a golf ball as well as an improved feel when the golf club head impacts a golf ball. The backside of the faceplate 14 is CNC milled to provide the central portion 30 with a greater thickness compared to that of the peripheral portion 32, effectively making the club face with a controlled thickness. The CNC milling technique is used to cut and achieve the exact dimensions of thickness at a given point of the club face 14. The circular marks 38 on the backside of the club face outside of the central portion 30 in FIG. 2 show the cuts resulting from the CNC milling process.

[0019] There are many advantages of having a variable thickness club face prepared according to the present invention. First, the CNC milling technique provides the desired precision and flexibility. Unlike other golf clubs made by a standard molding process, the CNC milling process can be programmed to change and obtain the desired thickness at a given area of the club face without having to construct new physical structures, i.e. making a new mold to accommodate a change in thickness, thereby reducing the operational costs, and providing the ease and ability to make golf clubs with different club face thickness. Second, the golf club head made according to the present invention can remain well balanced since no bulging weight or additional metal is added on the rear side of the club face as shown in other clubs known in the art. Thus, the present invention provides a well-balanced golf club head to enhance a golfer's performance. The golf club of the present invention also provides an extremely efficient energy transfer to a golf ball at the point of impact. Using the CNC milling, different portions of the club face can be easily made to have different thickness, and the process essentially enables one to make a club face with the desired stress pattern. Varying the thickness in the central portion 30 compared to that of the peripheral portion 32, has the effect of concentrating more metal within that central portion and providing greater impact strength.

[0020] The golf club head of the present invention is made by forging or casting each of the sole plate 12, the faceplate 14 and top plate 16. Generally, the faceplate 14 will be forged or cast so as to have an approximately constant thickness even though the striking surface is slightly convex. The hosel 18 is either cast, rolled or cut from a tube.

[0021] The faceplate 14 is then placed in a CNC mill machine wherein the backside 28 of the faceplate 14 is CNC milled. While the shape of the cuts made by the CNC machine as depicted in the figures appended hereto show a circular cut pattern, it should be understood that other noncircular cut patterns could be used. Thus, an oval shaped cut pattern having a long axis extending from the toe toward the heal may be preferred, alternatively, the cut pattern could have a roughly triangular shape or a shape generally matching the shape of the striking surface of the faceplate 14, as long as the approximate center of the pattern is positioned at an optimal point within the sweet spot for any particular club head design. By providing for uniformity in the decrease in the thickness around the periphery of the sweet spot while maintaining the preferred thickness within the sweet spot, the club head according to the present invention will have a more uniform trampoline effect when striking the ball.

[0022] After the backside 28 of the faceplate 14 is CNC milled, the faceplate 14 is attached to the sole plate 12 by welding. The hosel 18 is then attached to the faceplate 14 and to the sole plate 12 by spot welding. Next, the top plate is attached to the sole plate 12 and the faceplate 14 by welding. To finish the club head, a mill or grinding wheel is used to mill or grind off welds on the outside of the assemble club head. Finally the assembled club head is powder coated and/or painted.

[0023] Having thus described different embodiments of the invention, other variations and embodiments that do not depart from the spirit of the invention will become readily apparent to those skilled in the art. The scope of the present invention is thus not limited to any one particular embodiment, but is instead set forth in the appended claims and the legal equivalents thereof. 

What is claimed is:
 1. A method of forming a golf club head comprising: forming a sole plate; forming a faceplate having an approximately constant cross sectional thickness; forming a top plate; forming a hozel; shaping a backside of said faceplate on a CNC mill machine so that the cross sectional thickness of said faceplate decreases radially outward from a constant thickness sweet spot area; attaching said faceplate to said sole plate, said hozel to said sole plate and faceplate and said top plate to said sole plate, faceplate and hozel; and grinding and finishing the exterior surface of said club head.
 2. The method of claim 1 wherein said backside of said faceplate is CNC milled in a generally circular pattern.
 3. The method of claim 1 wherein said backside of said faceplate is CNC milled in a generally oval pattern.
 4. The method of claim 1 wherein said backside of said faceplate is CNC milled in a pattern generally matching the striking surface of said faceplate.
 5. The method of claim 1 wherein the approximate center of the CNC milled pattern is positioned at an optimal point within the sweet spot.
 6. The method of claim 1 wherein said faceplate is welded to said sole plate, said hozel is welded to said sole plate and faceplate and said top plate is welded to said sole plate, faceplate and hozel.
 7. The method of claim 1 wherein said faceplate, said sole plate and said top plate are formed by forging a metallic material.
 8. The method of claim 1 wherein said faceplate, said sole plate and said top plate are formed by casting a metallic material.
 9. A method of forming a faceplate for a golf club head comprising: forming a faceplate having an approximately constant cross sectional thickness; and shaping a backside of said faceplate on a CNC mill machine so that the cross sectional thickness of said faceplate decreases radially outward from a constant thickness sweet spot area having a thickness of between about 2.5 mm to 4 mm.
 10. A golf club head comprising: a sole plate; a faceplate having a sweet spot portion having an approximately constant cross sectional thickness and a CNC milled backside surrounding said sweet spot portion wherein the cross sectional thickness of said faceplate decreases radially outward from said sweet spot portion; a top plate; and a hozel, said sole plate, faceplate, top plate and hozel being assembled together to form said club head.
 11. The golf club head of claim 10 wherein said backside of said faceplate is CNC milled in a generally circular pattern.
 12. The golf club head of claim 10 wherein said backside of said faceplate is CNC milled in a generally oval pattern.
 13. The golf club head of claim 10 wherein said backside of said faceplate is CNC milled in a pattern generally matching the striking surface of said faceplate.
 14. The golf club head of claim 10 wherein the approximate center of the CNC milled pattern is positioned at an optimal point within the sweet spot.
 15. The golf club head of claim 10 wherein said faceplate is welded to said sole plate, said hozel is welded to said sole plate and faceplate and said top plate is welded to said sole plate, faceplate and hozel.
 16. The golf club head of claim 10 wherein said faceplate has a cross sectional thickness of about 3 millimeters in the sweet spot portion decreasing to about 2.5 millimeters at the outer peripheral edge of the CNC milled portion of said faceplate.
 17. The golf club head of claim 10 wherein said cross sectional thickness of said faceplate decreases by between about ten percent to twenty percent from the thickness of said faceplate in said sweet spot portion to the cross sectional thickness at the outer peripheral edge of the CNC milled portion of said faceplate.
 18. The golf club head of claim 10 wherein said faceplate is formed from a material selected from the group consisting of steel, stainless steel, titanium, and similar metallic materials.
 19. The golf club head of claim 10 wherein said sole plate, said faceplate and said top plate are formed from a material selected from the group consisting of steel, stainless steel, titanium, and similar metallic materials. 